1. Field of the Invention
The present invention relates generally to a linear motor and mounting arrangement. More particularly, the present invention relates to a linear motor with a keyed interface between the coil and a bracket and/or other mounting piece. Particular utility for the present invention is in the interchangeability of motor mounts and/or coils for linear motors, although other utilities are contemplated herein.
2. Description of Related Art
The current practice in the linear motor manufacturing industry is to build complete assemblies in anticipation of customer requirements. The motors are typically finish molded with a mounting bracket or attachment bar formed integrally to the assembly. Additionally, the coils are molded directly into the mounting bracket or attachment bar. While this is an efficient manufacturing technique, this technique does not permit a manufacturer or customer to change a coil and/or mounting bracket once assembled. Rather, the manufacturer or customer must fabricate or purchase an entire assembly for each given application.
The present invention solves these drawbacks by providing a keyed interface between the coil and the mounting bracket or attachment bar, thus permitting to interchange the coil and/or mounting bracket or attachment bar easily.
Accordingly, the present invention provides a linear motor assembly that uses keying technique to provide a uniform mechanical interface for linear motor coils to the mount or mounting bracket. This permits a molded coil assembly to be built as a subassembly, so that later insertion into brackets of varying configurations is possible. The keying technique locks the coil to the mount or mounting bracket, and accommodates many different bracket configurations without modification to the coil assembly. The coil is keyed to the bracket and attached with an adhesive such as an epoxy bond or thermal grease to improve the thermal dissipation from the motor to the mounting surface. This subassembly can be pre-manufactured and transformed to an application-specific assembly with relative ease in a short period of time. Bracket or mounting options may include various cooling features such as water or air-cooling. The subassembly can also be integrated directly to a linear system comprised, for example, of bearings or encoders. This eliminates the need for a separate mounting bracket, and improves heat dissipation.
To affix the mounting bracket or carrier to the coil, a pin or an area filled with a non-magnetic material (such as resin) may be used to prevent relative movement between the coil and the mount. The keying arrangement also allows for the installation of accessories such as commutation devices, speed sensors, thermal monitoring devices or encoders. A cover that is also keyed protects internal electrical connections. A similar slide-in and keying arrangement will apply to commutation devices used in linear applications.
In one embodiment, the present invention provides a linear motor and bracket assembly, comprising a coil winding having an I-beam cross section and having a first key portion formed thereon. The assembly also includes a bracket having a second key portion. The first key portion is mated with the second key portion. The mated first and second key portions are adapted to permit the bracket and the coil winding to slideably engage one another so that the bracket covers a portion of the coil winding.
In a second embodiment, the present invention provides a linear motor with keyed mounting arrangement that includes a coil winding having a first key portion formed therein and a carrier removably affixed to the coil having a second key portion. The first key portion is mated with the second key portion, and the mated first and second key portions are adapted to permit the carrier and the coil winding to slideably engage one another so that the carrier covers a portion of the coil winding. The motor also includes a base unit having a backiron and a magnet affixed thereto arranged about said coil.
Advantageously, the keying arrangement of the present invention provides intimate contact between the motor and mount for superior thermal performance, eliminates electrical problems inherent in coils that are molded directly into brackets, minimizes accumulated tolerances to improve mechanical rigidity, enables modular manufacturing strategy, and improves molding quality resulting in better protection of coils. Also, the present invention permits interchangeable mounting brackets for a range of applications, and interchangeable cable options for a range of applications
It will be appreciated by those skilled in the art that although the following Detailed Description will proceed with reference being made to preferred embodiments and methods of use, the present invention is not intended to be limited to these preferred embodiments and methods of use. Rather, the present invention is of broad scope and is intended to be limited as only set forth in the accompanying claims.
Other features and advantages of the present invention will become apparent as the following Detailed Description proceeds, and upon reference to the Drawings, wherein like numerals depict like parts, and wherein: